Thermoresponsive instrument



Patented May 10, 1921.

A. E. STACEY, Jn. THERMORESPONSIVE INSTRUMENT.

APPLICATION FILED SEPT. a, 19: 7.

A. E. STACEY, JR. THERMORESPONSIVE INSTRUMENT.

APPLICATION FILED SEPTw 6. 1917. 1,377,735. Patentgd May 10,1921

2 SHEEESSHEET 2.

ATTU/F/VEYJ ALFRED 1E. STACEY, 3B, OF CHICAGO, IJLLINOIS, ASSIGNOR T0CMRIEB; ENGINEER- INGr CORPOEATEON, OF NEW YORK, N- Y., A CORPORATIQN OFNEW WORK,

THERMORESIPONSIVE INSTRUMENT.

Specification of Letters Patent.

Patented May lift, 1921.

Application filed September 6, 1917. Serial No. ltwal.

T 0 all whom it may concern:

Be it known that l, ALFRED E. Smear, Jr., a citizen of-the UnitedStates, residing at Chicago, in the county of Cook and State ofIllinois, haveinvented a new and useful Improvement in ThermoresponsiveInstruments, of which the following is a specification.

This invention relates to humidity regulating apparatus and moreparticularly to regulators and apparatus for automatically varying oraltering the condition of humidity in a room or inclosure in a definitemanner, or according to a predetermined scale of change.

The apparatus is useful, for instance, for controlling the humidity ofthe air used for drying various materials where it is desired tograduate the drying action, using at the start an atmosphere having arelatively high humidity to prevent a too rapid drying of the materialand gradually, or by stages, reducing the humidity of the atmosphere toincrease its drying effect as the operation continues.

lhe humidity is regulated or altered under the control of a regulatorwhich comprises cooperating dry and wet bulb thermoresponsive elements,respectively responsive to changes in the dry and wet bulb temperaturesof the surrounding air, and means for varying the effect of the wet bulbtemperature on the wet bulb element, or causing the wet bulb temperatureto affect in succession differing areas of the wet bulb element.Preferably the wet bulb element is surrounded by pieces of wicking, orabsorbent material and a reservoir containing water is provided forindependently wetting the wicks in sucha way that as the water graduallyevaporates from the reservoir, one piece of wicking after anotherbecomes dry, and a gradually decreasing length of the wet bulb elementis kept wet or in condition to respond to changes in the wet bulbtempera ture. In this way there is a gradual increase in. depressionbetween the wet and dry bulb elements causing a gradual change in theirrelative or difi'erential action, and consequently a gradual change inthe humidity controlled by the regulator. Since the time required forevaporating the water depends upon conditions such as the volume ofwater used and the surface area of the water, the time of variation fromone humidity to another can be regulated as desired using waterreservoirs of difierent capacities and forms or changing the capacity ofthe reservoir.

In the accompanying drawings:

F gure 1 is a front elevation, partly in sect on, of a humidityregulator embodying the invention.

Fig. 2 is an end elevation thereof.

F 1g. 3 IS a sectional plan view thereof on line 3-3, Fig. 1.

Fig. 4: is a section thereof on line H, F 1g. 1.

Fig. 5 is a front elevation of a' regulator of modified construction.

Fig. 6 is a section thereof on line 6-6, Fig. 5.

Fig. 7 is a plan View thereof.

Referring first to the constructionshown in Figs. 1 to 4:, A. and 18represent respectively wet and dry bulb tlierinoresponsive elementswhich may be of any suitable form and material and may be operativelyasso ciated or connected with a regulating device C in such a way thatthe position of the device 0 and consequently its regulating action isdependent upon the relative or differential expansion andcontraction ofthe two elements A and B. With the exception of the means, hereinafterdescribed, for varying the effect of the wet bulb tempera ture on thewet bulbelement A, the regulator may be a wet and dry bulb hygrostat orinstrument of any suitable construction. As shown, it is constructedsubstantially like the regulator disclosed in Patent No. 1,138,082,granted May t, 1915, to Willis H. Carrier, assignor; that is, the twoelements A and B are parallel and one end of the dry bulb element bearsagainst the regulating lever or device C, while the opposite end of thiselement and the free end of the wet bulb element A bear against apivoted lever or frame D, which is held against the ends of the twoelements by a suitable spring E. The frame D is suitably fulcrumed, asby screws 61, on a suitable support F and has an adjustable bearingscrew y and an adjustable bearing block g. for the dry bulb and wet bulbelements A and B respectively. The spring E, which isattached atopposite ends to the frame D and to the support l draws the frame Dtoward and holds it in engagement with the expansible elements A and Bbut permits the frame to be moved in the opposite direction by theexpansion of the elements.

The fulcrum block g is adapted to be adjusted by ascrew 9 toward andfrom the fulcrum line of the frame D for regulating the motion of theframe D by the wet bulb element. The regulating lever or device C willremain stationary or will be moved in one direction or the other,depending upon the relative changes in length of the two elements A andB caused by changes in wet and dry bulb temperatures affecting them. Oneend of the lever or device C shown acts as a valve to control a bleederport it in a branch h of a pipe H which supplies compressed air to theactuating diaphragm or motor of the apparatus for changing the humidityof the atmosphere in the room in which the regulator is located. Thecompressed air supply pipe has a restriction k which permits only arestricted flow to the motor. When the bleeder port is closed by theregulating device C, the air will pass to the motor and operate it tomove the part actuated thereby in one direction, whereas, when theregulating device C is moved to open the bleeder port, the air willescape from the motor through this port faster than it can pass therestriction to the motor, thus permitting an opposite movement of thepart actuated by the motor. Any other instrumentalities governed by themovement of the lever (J, or other device actuated by the differentialaction of the thermoresponsive elements A and B, can be employed inplace of those described for effecting the regulated variation of thehumidity.

The means employed for changing the effect of the wet bulb temperatureon the wet bulb element, consists, in the regulator shown in Figs. 1 to4, of aplurality of pieces of wicking or absorbent material 10-surrounding the wet bulb element A, and

having extensions or portions 11 which dip' into water in a trough orreservoir 12 disposed lengthwise beneath the element A, whichishorizontal. The several wicks are spaced apart on the element A, orother suitable provision is made to prevent the water from communicatingfrom one wick to the next so that each wick must receive its waterindependently from the reservoir. The wicks dip into the water todifferent depths so that as the water evaporates from the reservoir itssurface drops below the depending portions of one wick after another,permitting one after another of the wicks to become dry. In this way agradually decreasing portion or areaof the element A is kept wet so asto be responsive to the wet bulb temperature of the air, and the amountof expansion or contraction of the element in response to changes in thewet bulb temperature of the air gradually alters, causing a gradualchange in the differential action of the two elements A and B on theregulating device. The reservoir 12 shown increases in depth lengthwise.Therefore, the water has the-greatest surface area and the rate ofevaporation is greatest when the reservoir is full, and the surface areaand rate of evaporation decreases as the level of the water lowers.- Byusing a reservoir of equal depth throughout, the rate of evaporationwould be more nearly uniform, and by using reservoirs of differentvolumes or by other appropriate changes in the proportion or relation ofthe parts it is possible to alter the rate of evaporation or graduatedaction of the regulator more or less as may be necessary to securedifferent desired results.

In the construction shown in Figs. 5 to 7, the wet and dry bulb elementsA and B are arranged vertically instead of horizontally but they areoperatively connected with the regulating device C and operate the samewater reservoir 15. The wet bulb element is surrounded by a plurality ofpieces of wicking or the like 16 and one or more holes 17 are providedin the wallsof the element A at different elevations through which thewater escapes from the chamber 13 to wet each of the wicks. The waterlevel will lower in the reservoir and in the hollow element A as thewater evaporates so that one wick after another will be left above thelevel of the water and will become dry, thereby gradually decreasing theportion of the element which is kept wet and responsive to the wet bulbtemperature of the air, and graduating the action of the instrument in amanner similar to that before described. In this arrangement also avariation in the volume or form of the reservoir 15 or of the hollowelement would give different results.

In either of the constructions described the number of the wicks and theextent of the wet bulb element which are wetted at first depends uponthe height to which the reservoir is filled. A desired initial wet bulbdepression can be secured by filling the reservoir to the appropriatelevel.

While in both of the constructions described the gradual reduction ofthe wetted surface of the wet bulb element is produced by theevaporation of the water, the inven tion is not necessarily restrictedto this way of accomplishing the reduction, since a similar result couldbe effectedin other ways.

The regulator can be utilized in different ways in drying processes forgraduating the drying actionas desired, as for example by using airhaving a constant dew point and controlling the temperature in .thedrying chamber by means of the regulator so as to give a graduallydecreasing relative humidity. Another method is to vary the relativenatures humidity by maintaining a constant temperature and graduallyvarying the dew point of the air used.

The regulator herein claimed can be used in connection with apparatussuch as disclosed in Letters Patent No. 1,812,759, dated August 12th,1919, granted to me.

I claim as my invention:

1. A thermoresponsive instrument including an element which is afiectedby changes in temperature, means for causing a portion of said elementto be subjected to the wet i bulb temperature of the surrounding air soas to respond to changes in said wet bulb temperature, and means forchanging the extent of the portion of the element which is subjected tothe wet bulb temperature, whereby the thermoresponsive action of theelement changes in accordance with the changes in extent of the portionof the element subject to the wet bulb temperature.

2. A thermoresponsive instrument including an element which is affectedby changes in temperature, means for enveloplng a portion of saidelement with moisture whereby the evaporation of said moisture causesthe enveloped portion of the element to respond to changes in the wetbulb temperature of the surrounding air, and means for changing theextent of the portion of the element Which is enveloped by the moisture,whereby the thermoresponsive action of the element changes in accordancewith the changes in extent of the portion of the element enveloped bythe moisture.

3. A thermoresponsive instrument including an element which is affectedby changes in temperature,-means for enveloping a portion of saidelement with moisture whereby the evaporation of said moisture causesthe enveloped portion of the element to respond to changes in the wetbulb temperature of the surrounding air, and means for reducing bypredetermined amounts the extent of the portion of the element which isenveloped by the moisture, whereby the thermoresponsive action of theelement changes in accordance with the reductions in the portion-of theelement enveloped by the moisture.

4. A thermoresponsive instrument comprising a thermoresponsive element,a plurality of wicks for evaporating moisture adjacent to differentportions of said element, and means for moistening said wicks andcausing one wick after another to become dry. L

5. A thermoresponsive instrument comprising a thermoresponsive element,a plurality of wicks for evaporating moisture adjacent to diilerentportions of said element, and a reservoir containing a liquid formoistening said wicks, saidreservoir and wicks being arranged to causeone wick after another to become dry as the liquid evaporates.

6. A thermoresponsive instrument comprising a thermoresponsive element,a plurality of wicks for evaporating moisture adjacent to difierentportions of said element, and a reservoir containing a liquid formoistening said wicks, said reservoir being arranged so that the liquidlowers out of contact with one wick after another as the liquidevaporates and its level lowers in the reservoir.

7. A thermoresponsive-instrument comprising wet and dry bulb elementswhich are respectively responsive to changes in the wet and dry bulbtemperatures of the surrounding air, a device which is actuated by thedifferential action of said wet and dry bulb elements, means for causingthe evaporation of moisture in the vicinity of said wet bulb element,and means for automatcally varying the extent of the portion of said wetbulb element which responds to changes in the wet bulb temperature.

8. A thermoresponsive instrument comprising wet and dry bulb elementswhich are respectively responsive to changes in the wet and dry bulbtemperatures of the surrounding air, a device which is actuated by thedifferential action of. said wet and dry bulb elements, means forcausing the evaporation of moisture in the vicinity of said wet bulbelement, and means for automatically reducing gradually the portion ofsaid element which responds to changes in the wet bulb temperature. 7

9; A thermoresponsive instrument comprising wet and dry bulb elementswhich are respectively responsive to changes in the wet and dry bulbtemperatures of the surrounding air, a device which is actuated by thedifferential action of said wet and dry bulb elements, a plurality ofwicks for evaporating moisture adjacent to. diflerent portions of saidwet bulb element, and means for moistening said wicks and causing onewick after another to become dry.

10. A thermoresponsive instrument comprising wet and dry bulb elementswhich are respectively responsive to changes in the wet and dry bulbtemperatures of the surrounding air, a device which is actuated by thedifferential action of said wet and dry bulb elements, a plurality ofwicks for evaporating moisture adjacent to difierent portions of saidwet bulb element, and a reservoir containing a liquid for moisteningsaid wicks, said reservoir being arranged so that the liquid lowers outof contact with one wick after another as the liquid evaporates and itslevel lowers in the reservoir.

Witness my hand this QFth day of August,

